Very impressive, and obviously a labour of love! As a calculator and SystemVerilog enthusiast, it's wonderful to see a project such as this come to fruition - congratulations!

I'm holding in my hand a 4-bit Von Neumann Mostek MK50310N that my father and I used to use to build calculators long ago. Although Mostek made chips for HP (such as the HP-35), they weren't commercially available, but the 50310 was. We could only dream of a project such as yours. I was happy when the "open source" NumWorks was released, but this project aligns more with my interests.

Will definitely install the Qt simulator - would be even better to build one IRL!